As methods for quantifying cyclodeviation in strabismus patient, Maddox double rod tests (Non-Patent Documents 1 and 2), major amblyoscopes (Non-Patent Document 2), new cyclo tests (Non-Patent Document 2), and the like are known.
The Maddox double rod test is performed by attaching two red and white Maddox rods to the trial frame and observing forward point light sources through the Maddox rods to perceive two linear light beams. By rotating one of the Maddox rods in the trial frame to measure a rotation angle until the two linear light beams become parallel to each other, so that the cyclodeviation can be quantitated. Although the methods are most widely used as quantitative methods because of low cost, since the scale of the trial frame is indicated in an increment of 5°, there is a problem in that detailed quantitation cannot be performed.
The major amblyoscope can perform detailed quantitation in an increment of 1°. However, it is assumed that the major amblyoscope is used in the installed state, and the device itself is extremely expensive.
The new cyclo test quantitates the cyclodeviation by observing a test chart printed with a half-moon figure arranged at a predetermined angle through red/green eyeglasses and allowing a patient to select the figure where the half-moon is viewed in parallel. There is a problem in that, in a case where horizontal strabismus or vertical strabismus is combined, it is difficult to perform the examination.